TWI227683B - Solid CO2 cleaning - Google Patents

Abstract

A method and apparatus are provided for removing solid and/or liquid residues from electronic components such as semiconductor wafers utilizing liquid or supercritical carbon dioxide which is solidified on the surface of the wafer and then vaporized and removed from the system. In a preferred embodiment the solidification and vaporizing steps are repeated (cycled) before removal of the CO2 from the vessel. The residues are carried away with the vaporized carbon dioxide.

Description

1227683 V. Description of the invention (1) [Technical Field] The present invention relates to the field of removing residues from the substrate surface, in particular, removing residues from electronic components such as integrated circuits and semiconductor wafers. Thing. [Prior art] Integrated circuits are formed of semiconductor substrates, and resistors, transistors, diodes, circuits, vias, and other electronic circuit components are formed on On the surface of the semiconductor substrate or on the surface of the half-body substrate. The electronic components contact the inside and outside of the semiconductor substrate, and a patterned conductor layer is formed on the semiconductor substrate by isolation of a dielectric iayer. Generally, in integrated circuit manufacturing technology, a dielectric layer is used to form a dielectric window and other devices, so that the patterned conductor layer and the electronic circuit elements separated by the dielectric layer can be electrically connected. The intermediary window and other devices and / or through the integrated layer can be formed by the lithography method and the subsequent plutonium method. The method 7 includes, but is not limited to, wet chemical etch and reactive ion etching. 〇n etch (RIE)) and dry plasma etch (d; y plasma etch) methods 〇fl Usually, the removal of each layer requires the use of a liquid or gaseous etchant. In some examples, when the reaction product is a fluid, it will be quickly removed from the reaction site so that the rate of etching is consistent. However, in certain examples, the reaction product is difficult to remove when it is an insoluble solid. eclipse

1227683 V. Description of the invention (2) The etchant can only gradually damage or weakly etch the part near the surface, and has no other effect, so it is very inefficient. In many etching processes, machinery uses a slurry to help the chemical etchant react, and the slurry contains an abrasive powder suspended in a suitable liquid medium (such as the etchant itself). This technology combines chemical and mechanical equipment to remove materials, called chemical mechanical polishing (CMP) ° CMP also has the opportunity to control the removal of materials along the plane, unlike pure fluid etching, which runs along the contour of the original surface. Etching. CMP is therefore widely used for planarization of integrated circuits. The disadvantage of CMP is that the CMP operation is completed, and some abrasive liquids tend to stay behind the abrasive surface. It is known to use super critical fluid (SCF) carbon dioxide to clean or strip wafers. In US Patent No. 5, 976, 264, the R IE residue is stripped from a CF4 type etchant, using SCF and a low-temperature aerosol, which allows a high-pressure gas-liquid mixture to be extended to a relatively low temperature at a low temperature. In areas of low pressure, the spray is cooled to make the mixture a solid residue. It is known to use solid carbon dioxide pel let, but it has not been implemented in a large amount in wafer bombardment. Because of the problems and defects of the prior art, one of the objects of the present invention is to provide a self-contained circuit from a substrate surface. And electronic components of semiconductor wafers

4IBM0386TW.ptd Page 9 12276683 5. Description of the invention (3) Method for removing solid and / or liquid residues A further purpose is to provide a device for removing solids and / or electronic components from integrated circuits and semiconductor wafers. Liquid residue. Other objects and advantages of the present invention will be apparent from the description of the specification. [Content] Phase = other purposes and advantages will be achieved by those skilled in the art based on the guidance of this invention; 'in the first aspect' A self-electronic component substrate, such as the removal of solids from semiconductor wafers and / or The method of liquid residue includes the steps of: * supplying a pressure container; supplying a semiconductor substrate in the container, and the residue removed by the semiconductor substrate; 〃 wanting to supply carbon dioxide in the container under a pressure and temperature; 2 3 Carcass, or above the critical pressure and temperature to make carbon dioxide as a boundary fluid; ~ ~ Reduce the surface temperature of the substrate so that the carbon dioxide contacting the surface of the substrate will turn into a solid on the surface; The temperature and / or pressure causes the state of the dioxygen liquid and / or gas in the container; the A-turn container removes carbon dioxide; and the container removes the semiconductor material.

4IBM0386TW.ptd Page 10 1227683 V. Description of the invention (4) Another aspect of the present invention is to provide-bulk wafers to remove solid and / or liquid residues i 70 substrates such as semiconducting-pressure vessels, suitable for containing-semiconductors Chips', including: a device for Yongyi and supply of carbon for pressure

A device that adjusts the pressure and holds the cry of annoyance #, — J becomes a liquid state or a supercritical state; fox x 'converts carbon dioxide *: the device' reduces the surface temperature of the substrate so that it contacts the substrate and the surface is opposite to the semiconductor substrate The surface turns into a solid;-a device that adjusts the pressure and temperature of the pressure vessel to a liquid and / or gas state; turns an emulsifying gorge into a state] a device that removes carbon dioxide from the container; where carbon dioxide is on the surface of the substrate When the solid state is changed to the liquid and / or gas state, the residue on the semiconductor substrate is removed. In another aspect of the present invention, before the carbon dioxide is removed from the container, the step of (recycling) reducing the surface temperature of the substrate and adjusting the temperature and pressure of the container to convert the carbon dioxide to a liquid and / or gas state. ^ [Implementation method] ~ In describing the preferred embodiment of the present invention, the features of the present invention will be described with reference to the drawings of FIG. I 1 c, but the features of the present invention are not shown to scale in the drawings.

1227683 V. Description of the invention (5) * On the one hand, the present invention removes residues from the substrate surface and solid or liquid residues that remain on the semiconductor surface after the semiconductor process steps such as RIE and CMP have been completed, using solid / liquid / Gaseous carbon dioxide is effectively removed. Ϊ0 The invention has the advantage that the density of carbon dioxide is different under different conditions. Dry ice (solid carbon dioxide) has a density of about 1.56. The density of liquid carbon dioxide is about 0.91 at 0 ° C and about 0.5 (less than 100 Opsi) at 31 ° C. When carbon dioxide solidifies, its volume is based on the following formula: volume mass / density, increased by three (3) times (0.5 to 1.56). Taking ice as an example, the ratio is much higher than ice. Liquid and supercritical carbon dioxide can effectively delaminating and / or remove particie. In particular, liquid or SCF carbon dioxide penetrates into the pores of the substrate and may leave residues. The present invention preferably utilizes a thermo electric / cooling stage to contact the wafer to solidify the carbon dioxide in contact with the wafer. Supercritical high pressure reactors can typically range, for example, from -180. (: To 100. 00 and to 1000 psi. The physical properties of carbon dioxide in various states are as follows: Rui dioxide physical state solid density liquid two 10 ° C 1.56 and -180 ° C liquid nitrogen 1.62 _ 0.9 at 0 ° C and 0 at 31 ° C,

SCF gas — > 31 ° C & > Aggregation of 0.09 and 30 ° C at 1200psiT 0.3-0.9 it; 0.3 at SFtCP

4IBM0386TW.ptd 1227683 V. Description of the invention (6). The two main aspects of the present invention are: (1) End point measurement (end ρ 〇i π tdetecti 〇η): If the wafer drops to -80C, for example, using liquid nitrogen The cold finger (c 〇1 d finger) cools the solid carbon dioxide on the surface of the wafer. It must be a little bit south at room temperature before being exposed to the air. During this process, dry nitrogen should be used to reduce moisture in the air. The wafer can be heated using ohms or possibly microwave or ultrasonic energy. Ohmic heating is considered the most efficient. (2) The wafer is returned to the atmosphere without agglomerated particles or water vapor on the wafer. Cold refers to the preferred or cooling control wafer construction stage (bu i 丨 d i ng stage) as described above. The highest level of pressure vessel steel is recommended to prevent cracking during pressure and thermal cycling. For safe use of the device, it is important to detect the solid carbon dioxide content on the surface and stop cooling. Oscillators need to be able to be used at low temperatures and be able to detect solids present on the surface through frequency changes. The term "substrate" as used herein includes what material controls subsurface features, such as caves, trenches, or 1 channels incorporated into the substrate and built features such as mesas . Cleaning such surfaces requires choosing f retentate rather than changing the surface shape (size). Substrates include, but are not limited to, " " made of semiconductors, metals, polymers or insulators. The term "supercritical fluid" as used herein means that a material is located here

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1227683 V. Description of the invention (7) In the pressure-temperature diagram of the material '~', the critical temperature is not lower than the critical pressure f Pi. The preferred supercritical fluid used in the present invention is a single sulphur dioxide or a mixture with other additives such as Ar, NH3, hydrazone, CHI ^, ^, n-4¾, Zr0,% 0 and the like. Surfactants, such as functional groups containing at least CFx, are used to connect liquid critical fluids. The term "super 6¾ boundary fluid" means that the material is above its critical point means a state such as-critical temperature [and a critical ink power ^, in two phases ... 〇pha + se) The material can reach equilibrium and become a separate One phase. Any of the 5 supercritical fluids known, such as carbon dioxide and / or any of the residues of the present invention. The preferred fluid or dibody is carbon dioxide. Other materials include rhenium, Guan 3, CH4, 3, n-c3H8, H20, N20, and similar materials. Any grade of material can be used in the present invention. If _: 3a of the Γ: grade material can be used with the conventional technology "No: = before the first two before entering the process cavity (-) ^ column (column) to purification.

$ P This material can also be combined with a surfactant that can remove semiconductors. Suitable additives include, but are not: J additives or additives. Particularly preferred among the additives is M. The materials mentioned by M.

1227683 V. Description of the invention (8) Typically, in the present invention, the material is transformed into a supercritical flow system under pre-pressurized to a pressure of 1 70 to 6 0 0 psi. It is better to pre-press up to 3000 psi before entering the process chamber. The supercritical fluid under pre-pressure is then transferred into a process cavity with a semiconductor to be cleaned.

The semiconductor used in the present invention is any semiconductor through r I E and any other I engraving technology mentioned above. Suitable semiconductor systems described herein include, but are not limited to, semiconductor wafers or semiconductor chips, ceramic substrates, patterned wafer structures, and similar materials. The process chamber pressure when removing the residue is typically about 0 7 0 to 600 Opsi, which is better than the process chamber pressure when removing the residue is 300 Ops i 〇 The process chamber temperature is greater than 31 ° C, and is usually about 40 ° C to 80 ° C. It is preferred that the temperature of the process cavity when removing the residue is about 400 ° C. # «To effectively remove residues from a semiconductor, the semiconductor needs to be exposed to a liquid or supercritical fluid for about 2 to 30 minutes or more, typically about 4 to 6 minutes, such as 5 minutes. Materials present in the process chamber may need to be cleaned or recycled in the device

4IBM0386TW.ptd Page 15 1227683 V. Description of Invention (9)-To form a closed reaction system. Such a closed reaction system can reduce the cost of manufacturing a clean wafer process. Referring to Fig. 1A, the numeral 10 shows a general high-pressure reactor. A chip 12 is located on a cooling / heating module 11. Module 11 is used to heat or cool wafers 12 as described below. The wafer 12 has particles 13 a and 13 b thereon, and the particles 14 are in the gap 20. The gas 15 is liquid carbon dioxide or SCF carbon dioxide in this reactor. Referring to FIG. 1B, the cooling / heating module 11 is activated to cool the wafer 12 and convert the liquid or SCF carbon dioxide 15 exposed on the surface of the lb wafer to a solid covering the surface of the wafer. Referring to FIG. 1C, the device is shown to have carbon dioxide vaporized and flushed from the pressure vessel 10 to remove particles 13a, 131) and 14. Film 1 2 is clean.

In one aspect of liquefaction or secondary media, the steps of cooling to solidify the carbon dioxide and heating the polluted material to secondary carbonize are repeated multiple times (cycles) to help expel < rinse. After one cycle of carbonization, the vaporization from the pressure vessel and although the present invention is specifically described,-the above-mentioned _ & π ^ U β, in the embodiment, it may be necessary to change, Modifications and variants-white iff

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4IBM0386TW.ptd Page 17 1227683 Brief description of the drawings-The features of the present invention are novel, and the features of the elements of the present invention are specifically proposed by the scope of patent application. Schematic illustrations are for illustration only and are not drawn to scale. However, the present invention includes the organization and method of operation, which can be understood with reference to the following detailed description of the invention and the accompanying drawings: Figure 1 A-1 C is a schematic diagram illustrating a high-pressure reactor containing a residue on the surface The wafer is inside and processed by the method and apparatus of the present invention. % · Symbols of the illustrated components 10 High-pressure reactor 11 Cooling / heating module 12 Wafer 13a, 13b, 14 Particles 15 Gas

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Claims (1)

92130037 VI. Application for patent scope 9a 11 -8 _ _ revision L A method for removing solid and / or liquid residues (residUe) from electronic component substrates, including the following steps: Pressure vessel; supply a semiconductor substrate in the container; 'the semiconductor substrate has residues to be removed; supply a material in the container, and use it at a pressure and temperature The material is a liquid, or the material is a supercritical fluid at a pressure and temperature above a critical pressure; reducing the surface temperature of the substrate so that it contacts the substrate is solid on the surface of the substrate ; Published Shi Pingxuan and changed the temperature and / or pressure of the container so that Geda, six touch poor / bucket, a 7 from the material in the mouth of the container to a liquid and / or gas state; from the container Removing the material; and removing the semiconductor material from the container. ^ 'In the patent sfl item, wherein the material is carbon dioxide. 3. The method according to item 丨 of the scope of the patent application, wherein the carbon dioxide contains a surfactant. 4. The method according to item 2 of the scope of the patent application, wherein the carbon dioxide is used to mix arsenic (Ar), ammonia (title 3), alkane (CH4), trifluoromethane ((: ding 3), ethane 41BM0386TW-Replacement Page 11 〇804.pt c Page 19 1227683 Case No. 92130037 9¾ 1L -a Wuyue Yue Amendment VI, Patent Application Scope (C2H6), Propane (n-C3H8), Water and Nitrous Oxide (N20) One or more. 5. The method according to item 2 of the scope of the patent application, wherein the oxidative breakdown is in a supercritical state. 6. The method according to item 1 of the scope of patent application, wherein the steps of reducing the surface temperature of the substrate to change the material to a solid and changing the temperature and / or pressure to change the material to a liquid and / or gas state are repeated one Or multiple times. 7 · —A device for removing solid and / or liquid residues from an electronic component substrate, comprising: a pressure vessel adapted to accommodate a semiconductor wafer; a device 'supplying the material to the pressure container; a device to adjust the The pressure and temperature of the pressure vessel are changed to a liquid state or a supercritical state. The reed port of the sapwood is prepared to reduce the surface temperature of the substrate so that the material contacting the substrate is transformed into a solid on the surface of the substrate; & It is necessary to transfer the material to a device, adjust the pressure and pressure ^ ^ ^ ^ ^ ^ ^, and change the pressure and temperature to liquid and / or gas state; another device, since the pressure is allowed to cry when the material is in The base 5 j divides the material; if it is in the liquid and / or gas state, it will be turned on and off in half plane: Guanggu / state, and then converted and removed. ^ Residue of body substrate is removed 4 i BM () 386TW-Replacement page 110804 · p t c 苐 Page 20! 227683 ~ ^ ____ Oxygen, application scope of patents, among which the material; · As described in the scope of patent application No. 7 on carbon. q ,, where the carbon dioxide is 9. The clothing gas n described in item 8 of the scope of patent application is in a supercritical state. 1 0 · Russ company directly made chrome 囹 chu n a! In which, the equipment is provided with the clothes described in 9 items of Ge Biao's patent siege. ^ ^ Repeat one or more times to reduce the surface temperature of the substrate to transform the di-emulsified plutonium into a solid and adjust the temperature and pressure to convert the dioxide. Steps in liquid and / or gaseous state. 4 [BM0386TW-Replacement page 丨 10804. p t c 21st tribute